Computer, CD transport or Network Player?

 I agree with shadorne, but one caveat - the quality of the design and implementation will decide among any of the 3 approaches.

Big money is not required, but careful attention to ground loops, noise injection and phase error will be important.  USB can be a problematic interface too.

The speakers, their locations, room treatments, and the SQ of the initial mastering & recording processes will all be much more important.

A rel. new DAC design will give better SQ/$ than older ones, so I would avoid used if older.

Your question would be an excellent one for the numerous audiophile and industry engineers at
https://www.computeraudiophile.com

I prefer to transfer (WiFi) data instead of music.  Data does not contain timing thus computer itself (speed, playback program etc) is not important.  It can be done using WiFi, Ethernet or Asynchronous USB.   When you connect transport to a DAC then most likely it will be done using digital cable and S/Pdif protocol.  Timing of the D/A converter clock will be dependent on incoming signal timing and many factors can affect it, including digital cable itself, playback program, computer speed/setup and electrical noise.

So it looks like either of these setups can work IF implementation is top notch. I'm not much for Spotify, Pandora, etc. because I like to listen to my own music. If I listen to an album sample & like most of what I hear I buy the CD. Would an SSD computer be better than the HDD I'm currently running? Does a network player with storage have any advantage over an SSD computer?

I can't answer your question about DAC implementation. But.... My buddy Ghosthouse suggested a number of years ago to try out Spotify. At first I treated it as you do: like music, then buy CD. Now I just go to Spotify and listen to it there. My CD collection is getting smaller now and I'm fine with that. The best CDs stay but those that aren't getting play go to the car for evaluation and if they don't pass the test they get added to the pile that goes to Fingerprints in Long Beach where I sell them. I usually pick up a some new CDs, but many less than I sell. I've also shelved ripping all my discs to an NAS. Lots of work for little return with online sources like Spotify and Tidal. Of course YMMV and this is but one mans IMO. Have fun!

I have seen claims that SSDs sound better than HDDs, also that the LCD drivers in a laptop create more noise in the digital stream than say a mac mini (more room between components, so the inverse square law helps quite a bit).

What I have not seen is actual measurements or reliable listening tests (blind, randomized, adequate sample size, etc.).

BTW, I am a WiFi type guy also.  It also breaks ground loops and is convenient.

Some problems are only going to be of importance if you are spending many thousands of $$ on a system.